Improvement in blackboard-erasers



G. H. GRANT. Blackboard-Hagar. No. 164,547, Patentedlunel5,l875.

fzzventoz UNITED STATES PATENT OFFIoE.

GEORGE H. GRANT, OF RICHMOND, INDIANA.

IMPROVEMENT IN BLACKBOARD-ERASERS.

Specification forming part of Letters Patent No. 164,547, dated J une 15, 1875; application filed April 29, 1875.

To all whom it may concern:

Be it known that I, GEORGE H. GRANT, of Richmond, in the county of Wayne and State of Indiana, have invented certain new and useful Improvements in Erasers or Rubbers for Removing Chalk from Blackboards; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to which it pertains to make and use the same, reference being bad to the accompanying drawing, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to devices for cleaning or removing chalk-marks from blackboards in use in schools, lecture-rooms, 850., and for other like purposes; and the invention consists in a cylindrical block covered with Axminster carpet or other suitable material, and attached to a suitable handle by pivotal end bars, the eraser and handle being so arranged that the cylinder presses against the handle sufficiently to hold the rubber in place when in use without revolving, yet permit of the cylinder being turned when a new rubbing-surface is desired, all as hereinafter more fully set forth.

' In the accompanying drawings, Figure 1 is a perspective view of my improved cylindrical blackboard rubber or eraser. Fig. 2 is a longitudinal sectional view of the same. Fig. 3 is an end view of same; and Fig. 4 is an end view, showing a modified form of the handle of same.

Referring to the parts by letters, A B represent a cylindrical block of wood or other suitable material, covered with Axminster carpet or other suitable material for cleaning blackboards, 8m. 0 is the handle, made of wood or other suitable material, and preferably of the oval form shown in Figs. 1 and 3 of the drawings; but it may be made of any suitable or desirable form, and may be made so as to press against the cleaning material which covers the cylinder with suflicient friction to prevent the latter from turning when the rubber is in use. D D represent frictional end bars, of sole-leather or any suitable material and d d d d are screws or bolts, which are passed through the end bars D D into the cylindrical block A and handle 0, for the purpose of attaching them together, and to form frictional pivots or spindles, upon which one or other, or both, may revolve. The

heads of the bolts or screws d are countersunk in the end bars.

These pivots may be made sufficiently stiff or rigid to hold the rubber in proper working position without requiring the handle to press against the material of the rubber.

The handle shown in Fig. 4 of the drawings is pivoted eccentrically, so that, by turning it, the pressure against the rubbing material, and the consequent rigidity of the handle with the rubber, may be increased or lessened at pleasure; and from the peculiar form of the under side of the handle 0, the same effect may be produced by turning it slightly on its pivots.

The peculiar advantage of this cylindrical form of rubber will be obvious to those skilled in the art.

The ordinary rubbers now in use present a comparatively broad fiat surface to the board, which is soon matted down and filled with chalk, so as to render it hard and positively injurious to the blackboard, which soon becomes scratched through the use of such rubber.

My cylindrical rubber comes in contact with the board on a single line only, and hence every part of its entire surface may be used in succession, and no matting down or filling the body of the fibrous material with chalk will be experienced.

These rubbers may also be constructed with great economy, are neat, strong, and durable, and thoroughly effective in their operation.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is'

1. The cylindrical rubber or brush A B, handle 0, and frictional end bars D D, combined and arranged to operate substantially as and for the purpose specified.

2. The combination of the oval or eccentrically-pivoted handle 0 with the cylindrical rubber or brush A B, end bars D D, and pivotal bolts or screws 01 d, all arranged to oper- Ialte1 substantially as and for the purpose speci In testimony that I claim the foregoing as my own invention I affix my signature in presence of two witnesses.

GEORGE H. GRANT.

Witnesses:

TURNER W. HAYNES, WILLIAM F. SPENCER. 

